RFR: 8285956: (fs) Excessive default poll interval in PollingWatchService [v7]

[Tyler Steele]

> PollingWatchService.java contains the WatchService and WatchKey implementation for AIX and BSD. When a Path is [register](https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/nio/file/Path.html#register(java.nio.file.WatchService,java.nio.file.WatchEvent.Kind...))ed this implementation creates a  polling thread to monitor for file system changes. Currently, this thread waits 10 seconds before it's first poll, and then waits 10 seconds between subsequent polls. This interval leads to sluggish performance.
> 
> This PR makes the following changes:
> - Sets the initial interval to 1 second regardless of the period.
> - Change the default period to 1 second.
> 
> All tests in `test/jdk/java/nio/file/WatchService` passing.

Tyler Steele has updated the pull request incrementally with one additional commit since the last revision:

  Adds comments to polling thread constant values

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8479/files
  - new: https://git.openjdk.java.net/jdk/pull/8479/files/65eb8f12..6328307a

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8479&range=06
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8479&range=05-06

  Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8479.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8479/head:pull/8479

PR: https://git.openjdk.java.net/jdk/pull/8479